From b20fdff5214e760205f7fccbce6848c545f12b0b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Forsman?= <bjorn.forsman@gmail.com>
Date: Fri, 23 Dec 2016 17:42:05 +0100
Subject: [PATCH] nixos/prometheus: make
 scrapeConfigs.*.static_configs.*.labels optional

...by providing a default value of "no labels" (an empty attrset).

Without this change we get

  $ nixos-rebuild test -I nixpkgs=.
  building Nix...
  building the system configuration...
  error: The option `services.prometheus.scrapeConfigs.[definition 1-entry 1].static_configs.[definition 1-entry 1].labels' is used but not defined.

which is unneeded, because labels _are_ optional.
---
 nixos/modules/services/monitoring/prometheus/default.nix | 1 +
 1 file changed, 1 insertion(+)

diff --git a/nixos/modules/services/monitoring/prometheus/default.nix b/nixos/modules/services/monitoring/prometheus/default.nix
index d692dd5fc79..a07445ce167 100644
--- a/nixos/modules/services/monitoring/prometheus/default.nix
+++ b/nixos/modules/services/monitoring/prometheus/default.nix
@@ -191,6 +191,7 @@ let
       };
       labels = mkOption {
         type = types.attrsOf types.str;
+        default = {};
         description = ''
           Labels assigned to all metrics scraped from the targets.
         '';